There are dozens of times throughout my life where I wanted God to fix something, to intervene, to heal...sometimes He did and sometimes He didn't.
But, I do NOT believe that He failed me in anyway. He does not take orders from me. He can see the big picture while I can only see as far as the "headlights." Therefore, sometimes it's an issue of timing (not the right time) or it's not the right situation for me in the grand scheme of things. But, I think it is always a lesson for me, a molding of character, and a strengthening of my faith.
God doesn't need to show up since He is always there. A favorite song of mine has a chorus that was taken from words scratched on the wall of a WWII Nazi concentration camp:
"I believe in the sun even when it's not shining,
I believe in love even when I don't feel it,
and I believe in God even when He is silent."